Commit message: Fix tf.raw_ops.EditDistance vulnerability with negative indices.

Check that indices are non-negative. Fix several identical code sites.
Clean up grammar in error message.

PiperOrigin-RevId: 445442017
CVE: CVE-2022-29208
CWE: CWE-787
Vulnerability description: TensorFlow is an open source platform for machine learning. Prior to versions 2.9.0, 2.8.1, 2.7.2, and 2.6.4, the implementation of `tf.raw_ops.EditDistance` has incomplete validation. Users can pass negative values to cause a segmentation fault based denial of service. In multiple places throughout the code, one may compute an index for a write operation. However, the existing validation only checks against the upper bound of the array. Hence, it is possible to write before the array by massaging the input to generate negative values for `loc`. Versions 2.9.0, 2.8.1, 2.7.2, and 2.6.4 contain a patch for this issue.

Project: tensorflow
File: edit_distance_op.cc

  void Compute(OpKernelContext* ctx) override {
    const Tensor* hypothesis_indices;
    const Tensor* hypothesis_values;
    const Tensor* hypothesis_shape;
    const Tensor* truth_indices;
    const Tensor* truth_values;
    const Tensor* truth_shape;
    OP_REQUIRES_OK(ctx, ctx->input("hypothesis_indices", &hypothesis_indices));
    OP_REQUIRES_OK(ctx, ctx->input("hypothesis_values", &hypothesis_values));
    OP_REQUIRES_OK(ctx, ctx->input("hypothesis_shape", &hypothesis_shape));
    OP_REQUIRES_OK(ctx, ctx->input("truth_indices", &truth_indices));
    OP_REQUIRES_OK(ctx, ctx->input("truth_values", &truth_values));
    OP_REQUIRES_OK(ctx, ctx->input("truth_shape", &truth_shape));

    OP_REQUIRES_OK(
        ctx, ValidateShapes(ctx, *hypothesis_indices, *hypothesis_values,
                            *hypothesis_shape, *truth_indices, *truth_values,
                            *truth_shape));

    TensorShape hypothesis_st_shape;
    OP_REQUIRES_OK(ctx,
                   TensorShapeUtils::MakeShape(
                       hypothesis_shape->vec<int64_t>().data(),
                       hypothesis_shape->NumElements(), &hypothesis_st_shape));
    TensorShape truth_st_shape;
    OP_REQUIRES_OK(ctx, TensorShapeUtils::MakeShape(
                            truth_shape->vec<int64_t>().data(),
                            truth_shape->NumElements(), &truth_st_shape));

    // Assume indices are sorted in row-major order.
    std::vector<int64_t> sorted_order(truth_st_shape.dims());
    std::iota(sorted_order.begin(), sorted_order.end(), 0);

    sparse::SparseTensor hypothesis;
    OP_REQUIRES_OK(ctx, sparse::SparseTensor::Create(
                            *hypothesis_indices, *hypothesis_values,
                            hypothesis_st_shape, sorted_order, &hypothesis));

    sparse::SparseTensor truth;
    OP_REQUIRES_OK(ctx, sparse::SparseTensor::Create(
                            *truth_indices, *truth_values, truth_st_shape,
                            sorted_order, &truth));

    // Group dims 0, 1, ..., RANK - 1.  The very last dim is assumed
    // to store the variable length sequences.
    std::vector<int64_t> group_dims(truth_st_shape.dims() - 1);
    std::iota(group_dims.begin(), group_dims.end(), 0);

    TensorShape output_shape;
    for (int d = 0; d < static_cast<int>(group_dims.size()); ++d) {
      output_shape.AddDim(std::max(hypothesis_st_shape.dim_size(d),
                                   truth_st_shape.dim_size(d)));
    }
    const auto output_elements = output_shape.num_elements();
    OP_REQUIRES(
        ctx, output_elements > 0,
        errors::InvalidArgument("Got output shape ", output_shape.DebugString(),
                                " which has 0 elements"));

    Tensor* output = nullptr;
    OP_REQUIRES_OK(ctx, ctx->allocate_output("output", output_shape, &output));
    auto output_t = output->flat<float>();
    output_t.setZero();

    std::vector<int64_t> output_strides(output_shape.dims());
    output_strides[output_shape.dims() - 1] = 1;
    for (int d = output_shape.dims() - 2; d >= 0; --d) {
      output_strides[d] = output_strides[d + 1] * output_shape.dim_size(d + 1);
    }

    auto hypothesis_grouper = hypothesis.group(group_dims);
    auto truth_grouper = truth.group(group_dims);

    auto hypothesis_iter = hypothesis_grouper.begin();
    auto truth_iter = truth_grouper.begin();

    auto cmp = std::equal_to<T>();

    while (hypothesis_iter != hypothesis_grouper.end() &&
           truth_iter != truth_grouper.end()) {
      sparse::Group truth_i = *truth_iter;
      sparse::Group hypothesis_j = *hypothesis_iter;
      std::vector<int64_t> g_truth = truth_i.group();
      std::vector<int64_t> g_hypothesis = hypothesis_j.group();
      auto truth_seq = truth_i.values<T>();
      auto hypothesis_seq = hypothesis_j.values<T>();

      if (g_truth == g_hypothesis) {
        auto loc = std::inner_product(g_truth.begin(), g_truth.end(),
                                      output_strides.begin(), int64_t{0});
        OP_REQUIRES(
            ctx, loc < output_elements,
            errors::Internal("Got an inner product ", loc,
                             " which would require in writing to outside of "
                             "the buffer for the output tensor (max elements ",
                             output_elements, ")"));
        output_t(loc) =
            gtl::LevenshteinDistance<T>(truth_seq, hypothesis_seq, cmp);
        if (normalize_) output_t(loc) /= truth_seq.size();

        ++hypothesis_iter;
        ++truth_iter;
      } else if (g_truth > g_hypothesis) {  // zero-length truth
        auto loc = std::inner_product(g_hypothesis.begin(), g_hypothesis.end(),
                                      output_strides.begin(), int64_t{0});
        OP_REQUIRES(
            ctx, loc < output_elements,
            errors::Internal("Got an inner product ", loc,
                             " which would require in writing to outside of "
                             "the buffer for the output tensor (max elements ",
                             output_elements, ")"));
        output_t(loc) = hypothesis_seq.size();
        if (normalize_ && output_t(loc) != 0.0f) {
          output_t(loc) = std::numeric_limits<float>::infinity();
        }
        ++hypothesis_iter;
      } else {  // zero-length hypothesis
        auto loc = std::inner_product(g_truth.begin(), g_truth.end(),
                                      output_strides.begin(), int64_t{0});
        OP_REQUIRES(
            ctx, loc < output_elements,
            errors::Internal("Got an inner product ", loc,
                             " which would require in writing to outside of "
                             "the buffer for the output tensor (max elements ",
                             output_elements, ")"));
        output_t(loc) = (normalize_) ? 1.0 : truth_seq.size();
        ++truth_iter;
      }
    }
    while (hypothesis_iter != hypothesis_grouper.end()) {  // zero-length truths
      sparse::Group hypothesis_j = *hypothesis_iter;
      std::vector<int64_t> g_hypothesis = hypothesis_j.group();
      auto hypothesis_seq = hypothesis_j.values<T>();
      auto loc = std::inner_product(g_hypothesis.begin(), g_hypothesis.end(),
                                    output_strides.begin(), int64_t{0});
      OP_REQUIRES(
          ctx, loc < output_elements,
          errors::Internal("Got an inner product ", loc,
                           " which would require in writing to outside of the "
                           "buffer for the output tensor (max elements ",
                           output_elements, ")"));
      output_t(loc) = hypothesis_seq.size();
      if (normalize_ && output_t(loc) != 0.0f) {
        output_t(loc) = std::numeric_limits<float>::infinity();
      }
      ++hypothesis_iter;
    }
    while (truth_iter != truth_grouper.end()) {  // missing hypotheses
      sparse::Group truth_i = *truth_iter;
      std::vector<int64_t> g_truth = truth_i.group();
      auto truth_seq = truth_i.values<T>();
      auto loc = std::inner_product(g_truth.begin(), g_truth.end(),
                                    output_strides.begin(), int64_t{0});
      OP_REQUIRES(
          ctx, loc < output_elements,
          errors::Internal("Got an inner product ", loc,
                           " which would require in writing to outside of the "
                           "buffer for the output tensor (max elements ",
                           output_elements, ")"));
      output_t(loc) = (normalize_) ? 1.0 : truth_seq.size();
      ++truth_iter;
    }
  }